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Combo Snow Gun 


Combo Snow Gun 

Written By: Steven Lemos 


Humidity gauge (1) 

Thermometer (1) 
Wrench (1) 


Tee pipe fitting (4) 

Ball valve (1) 

Pipe nipples (3) 

You can vary these lengths, but you 

need at least 4" between the nucleation 

nozzle and the first bulk nozzle. 

Pipe nipples (3) 

You can vary these lengths, but you 

need at least 4" between the nucleation 

nozzle and the first bulk nozzle. 

Nozzle tip (1) 

TeeJet/Spraying Systems part #TP8010. 

These are available from agriculture 

equipment suppliers; look online or see for a list of dealers. 

Nozzle tips (2) 

TeeJet/Spraying Systems part #TP5004 

or #TP6504. These are available from 

agriculture equipment suppliers; look 

online or see for a list of 


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Pagel of 10 

Combo Snow Gun 

Nozzle bodies (3) 

TeeJet type 3/8TT. part #CP1324 

Nozzle caps (1) 

TeeJet type 3/8TT, part #CP1325 

Garden hose fitting (1) 

for air line 

Fitting (1) 

to attach your water line: some are 1 / 4 " 

or 3/8" quick-disconnect, some are 


Pressure gauge (1) 

Pipe plug (1) 

// not using pressure gauge 

Check valve (1) 

// you can find one. I used aA 3 A" valve 

with two 3/8" reducers. 

Garden hose (1) 

for air line 

Water line (1) 

like the hose that comes with a pressure 


Pressure washer (1) 

or other water pump capable of at least 

Air compressor (1) 

capable of 6 cubic feet per minute (cfm) 


So it doesn't snow enough where you live? Fear not — if it gets cold, you can cover that 
front lawn in white, fluffy snow with your own homemade snow gun. All you need are a few 
items from your local hardware store, some quality spray nozzles, and access to a pressure 

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Combo Snow Gun 

washer and an air compressor. 

This snow gun is based on an internal-mixing "combo" design I found at . It mixes pressurized air and water internally and sprays them out 
through 2 types of nozzles that work together cleverly. Just wrap teflon plumber's tape on all 
the pipe threads, then twist it together tightly as you see it in the diagram. 

To understand how it works, remember high school chemistry: the smaller a particle is, the 
more surface area it has relative to its volume. Generally, that makes it easier to freeze. 
This is the job of the nucleation nozzle; it breaks the water into very small particles, making 
it possible for them to "nucleate," or freeze quickly around their own impurities, thus 
generating a spray of superfine ice crystals. 

This "ice mist" then crosses the spray from the 2 bulk nozzles, which supply the bulk of the 
water for our snowmaking. Droplets from the bulk spray freeze to the nucleated ice crystals, 
creating fluffy snow. 

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Combo Snow Gun 

Step 1 — Get some nozzle knowledge. 

folume (GPM) at Various Pressures [PSD 

• Nozzles are the most important purchase for your snow gun. To make an effective snow 
gun you have to match the bulk nozzles to the nucleation nozzles, and match both to the 
characteristics of your compressor and pressure washer. 

• A good brand is TeeJet; they make spray nozzles for agricultural use and these work great 
for snow guns. TeeJet nozzles are numbered by their output; on their face is a 4 or 5 digit 
number whose first 2-3 digits represent spray angle, and whose last 2 represent flow at 40 
pounds per square inch (psi), measured in gallons per hour (gph). For example, nozzle 
8005 translates to an 80° spray angle and 0.5gph flow at 40psi. 

• The trick to matching your bulk nozzles to your nucleation nozzles is that the nucleation 
spray must engulf the bulk spray, or else the bulk spray will have wet edges (spraying 
non-snow, just water). But you don't want the nuc spray overly wide, or you'll lose 

• Here are some good angles to use: 40° bulk and 65° nucleation, or 50° bulk and 80° nuc. 
(I used 65°/80° here because that's what was in stock.) 

• The photo shows a list of nozzle volumes (gpm) at various pressures (psi). 

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Combo Snow Gun 

Step 2 — Choose your pipe and consider the pressure. 

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Combo Snow Gun 

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• This snow gun uses 3/8" ID pipe 
made for home use. I used a 
garden hose connection for the air 
line, because quick-disconnect 
fittings are more prone to freeze- 
ups, but the water line is high- 
pressure hose so you'll need to use 
a quick-disconnect or a specific 
threaded fitting there. 

• Pipe material is another concern. 
Typical galvanized steel pipe is 
rated for 150psi-300psi; it's 
possible to run it close to 600psi, 
but anything over 700psi and the 
chances of pipe bursts are greater. 
Brass is better, with a pressure 
rating from 125psM-00psi. 
Stainless steel is the safest, rated 
for 3,000psi, but I don't think 
people want to spend $15 per 3/8" 
tee fitting. 

• It's a good idea to have a pressure 
gauge that reads to 1,000psi, to 
control how much pressure is going 
into the gun. I run my brass gun at 
450psi-700psi, but keep in mind, 
higher pressure will wear more on 
your nozzles, pipe, and pump, and 
you exceed the ratings at your own 

• The ball valve is in place to adjust 
the water pressure going to the 
nucleation nozzle, and this takes 
some playing around with to get it 
right. If the water pressure's too 
high, you'll get a misty fog and 

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Combo Snow Gun 

puny snow production. If it's too 
low, you'll get big droplets that 
won't freeze before reaching the 
bulk spray, and you'll be making 
very wet snow. 

Step 3 — Find a compressor and pressure washer. 

• The snow gun runs on 40psi-70psi from the air compressor. It is highly recommended that 
you use an oil-lubricated compressor; this will allow hours of operation without any trouble. 
A good compressor should be able to output 6cfm at 40psi. 

• A good pressure washer will feed about 2 gallons per minute (gpm) at 450psi. 

Step 4 — Make the assembly. 

• The air line uses a garden hose 
fitting (1) to reduce freeze-ups, and 
a check valve (2) to protect the 
compressor. The water line's fitting 
(3) depends on your high-pressure 

• The gauge (4) displays overall 
pressure. The ball valve (5) lets 
pressurized water mix with air for 
the nucleation nozzle (6), which 
must be at least 4" from the bulk 
water nozzles (7). 

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Combo Snow Gun 

Step 5 — Snowmaking 101. 

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Combo Snow Gun 

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• To make snow, you don't 
necessarily need temperatures 
below 32° F — you just need them 
below freezing on the wet bulb 
temperature chart in the files 
section, which takes into account 
the relative humidity of your 
location. For example, at 95% 
humidity you need temperatures 
27° F or colder, but at 10% 
humidity you can start making 
snow at just 39 °F. 

• First, close the ball valve, so you 
don't flood your compressor. Turn 
on the water supply — but not the 
pressure washer yet — and make 
sure water's coming out of the bulk 
nozzles. Make sure there's no ice 
in your pressure washer — ice 
could destroy the unit or hurt 
someone — then turn on the 
pressure washer. 

• Turn on the air compressor, letting 
the pressure reach 40psi or more. 
Now start to open the ball valve 
just a little, so you get a superfine 
mist from the nucleation nozzle. 
Check the compressor and make 
sure the air pressure is above 
60psi. You should be making snow! 

• To check your snow's quality, put 
your coat sleeve in front of the 
spray; the snow should bounce 
right off. Check the gun 
periodically, making sure your 
nucleation nozzle isn't freezing up; 

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Combo Snow Gun 

if it is, open the ball valve a bit 
• Elevating the gun gives the snow 
more time to freeze before hitting 
the ground; you can use a ladder or 
make a stand out of wood or PVC 

Output and Precautions 

So I'm sure you're wondering, "How much snow can I actually make with this thing?" The answer 
depends on how much water you're flowing, and this depends on the water pressure and air 
pressure. The more water you're able to flow through the gun, the more snow you'll have piling 
up. Expect 2"-5" per hour, at 2gpm flow. Some advice to keep in mind: 

Don't shoot snow against the wind. You'll get freeze-ups. Go with the wind to make life easier. Install a check valve between 
your compressor and the snow gun; this will prevent flooding of your compressor. Air compressors are loud, so if you plan to 
make snow overnight or in the early morning, be considerate of neighbors. Your snow gun will hiss like a gas leak, so inform 
your neighbors that it's nothing to be afraid of. Wear plenty of warm clothing when you're making snow, because it will be 
cold outside, and when you're working with water and metal pipe it will seem a lot colder. Wear good waterproof gloves. Don't 
leave your hose outside with water in it, or it will freeze and possibly split. Bring it inside. If it does freeze, throw it in a 
bathtub of warm water. Last but not least, have fun! 

Special thanks to the contributors to, where much of this information came from. 
All images, except Step 4, courtesy of James Moss of 

This project first appeared in MAKE Volume 21 . page 125. 

last generated on 201 2-1 2-20 02:24:1 1 PM. 

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